Crankshaft Position Sensor

[geobern]

my 2021 Yukon Duramax has twice “jerked” or skipped at highway speed. First in August and again last week. We are now waiting for back order crankshaft position sensor parts. Anyone else had this problem? And how long can we expect to be without our Yukon? Thanks.

 

[geobern]

Twice

 

[StephenPT]

Lots of GM parts have been on backorder for the last 3 to 4 years. No real way to know how long the part will take for the dealer to get, but if possible you might try ordering it from one of the online GM parts suppliers.

Looks like the GM part number is 40009075.

Just curious, were there DTCs the dealer pulled that you can share? Did the jerking issue cause a check engine light?

 

[geobern]

Thanks for the reply. The first message was related to exhaust emissions systems and then a message limiting how far I could drive at certain speed. Regular speed for 175 mi. Then 65 mph for 175 mi. And so on. It happened that I parked overnight before I got to use up the first 175 mi. Overnight the system reset and no sys messages in the morning. Then driving home (I was on a trip) the jerk thing happened again and the same messages appeared. So I took it to the dealer when I got home and they’ve had it since.
No, I don’t have the codes.

 

[Jay P Wy]

Have you had this Yukon since new? There was an issue with early LM2s that caused an intermittent crank - no start issue. It urned out to be an issue with the cam position sensor not generating a signal fast enough. They also found a few (very small number) that left the factory where the metal wheel on the cam was bent/warped causing some weird issues. One of the early attempts to fix involved putting a shim under the cam position sensor (didn't work). A later software update did fix the issue. If you aren't the original owner the added shim may have been installed and cause the issue. I had a 2021 Silverado with the issue and the software did fix the issue. Duramax forums and GMtrucks.com forums tend to have a lot more info on the LM2/LZ0.

 

[geobern]

Have you had this Yukon since new? There was an issue with early LM2s that caused an intermittent crank - no start issue. It urned out to be an issue with the cam position sensor not generating a signal fast enough. They also found a few (very small number) that left the factory where the metal wheel on the cam was bent/warped causing some weird issues. One of the early attempts to fix involved putting a shim under the cam position sensor (didn't work). A later software update did fix the issue. If you aren't the original owner the added shim may have been installed and cause the issue. I had a 2021 Silverado with the issue and the software did fix the issue. Duramax forums and GMtrucks.com forums tend to have a lot more info on the LM2/LZ0.

I am the originally owner and am not aware of a shim insertion but I had a similar incident in August and don’t recall what was done. I’ll check with the dealer this week and also check with the other sites for info. Thanks a lot for the inf. This is a huge help… I hope.

 

[SC2CO_TAHOE]

Wow! This is really helpful. My 2022 D-max has been at the dealer for over a month waiting for the crankshaft sensor. I have a Jeep Renegade as a loaner . I stopped by today and the service rep told me the part is still on back order; there are only 4 available in the US and the dealers that have them don’t want to give them up! How long did it take to have your sensor come in? Thx,

 

[geobern]

Update: Crank Position Sensor came after 3+ weeks. Dealer now says that didn’t solve the problem so they’re looking at the whole engine wiring harness for chaffing or terminal fretting after consulting with GM. Any ideas out there?

 

[StephenPT]

Hopefully your dealer is using this TSB as a guide to inspect areas of the harness that are known to have chaffing issues. Not all pictures in the TSB apply to the LM2, but skim through it and you'll see which ones do.

https://static.nhtsa.gov/odi/tsbs/2022/MC-10227798-0001.pdf

 

[UsualSuspect]

Our shop uses some sort of cloth tape to wrap areas that are prone to chafing, usually when upfitting them. I asked and was told it's Wire Harness Automotive Cloth Tape, made by Maxwell Manufacturing. I always thought we used plastic or vinyl tape, but I was told this tape is the best you can find to repair, or wrap wiring in that is in areas subject to movement. I grabbed a few rolls to throw in the Yukon and the Sierra just in case.